Brake-operating mechanism



E. B. MEAD.

BRAKE OPERATING MECHANISM.

APPUCATION FILED MAR. 10, 1919- Patented Mar. 29, 1921.

UNITED STATES PATENT OFFICE.

EZRA B. MEAD, OF QTTUMWA, IOWA, ASSIGNDR 'IO OTTUMWA IRON WORKS, OF OT'IUMWA, IOWA, A CORPORATION OF IOWA.

BRAKE-OPERATING MECHANISM.

T 0 all whom it may concern:

Be it known that I, EZRA B. MEAD, a

citizen of the United States, residing in Ottumwa, in the county of Wapello and State of Iowa, have invented a new and useful Improvement in Brake-Operating Mechanism, of which the following is a specification. v v

This invention relates in general to controls for brakes for "mine hoists and other apparatus and although the invention is hereinafter shown and described in connection with a mine hoist control of the character disclosed in my co-pending application Seria1 No. 851,891 it will be readily understood that it may with equal [value be used in other connections.

The invention contemplates the use of oil or other incompressible liquid supplied under pressure to control the operatlon of the brake, and with the resulting advantages of such a control medium the provision also of the advantages that ordinarily only attend the use of a compressible medium such as air, and this without the presence of the disadvantages heretofore believed inherent when either of these mediums have been employed. The air being highly compressible and elastic has not provided a control of sufiicient stability in apparatuses of the character of mine hoists so that when the brakes were moved the brake weight had a marked tendency to bounce. The use of oil or like liquid provides a positive and quick operating control, but is highly sensitive and to prevent too sudden stoppingand starting of the cage requires close attention to the careful manipulation of the brake control valve. It is a principal purpose of my invention to provide against this sudden starting and stopping under normal action of the cage in a control using an incompressible liquid as oil to the end that the positive action may still be preserved and this action instead of being instantaneous shall Y be spread out over a small period of time,

so that the starting and stopping must automatically be smooth and without abrupt jar.

My invention contemplates to this end the utilization of a force controlled by the pressure of the oil itself for delaying or spreading the application of the full pressure over a small or even a minute period of time.

The means or agency I prefer to employ for this purpose is an air pocket appropri- Specification of Letters Patent.

.Patented Mar. 29, 1921.

Application filed March 10, 1919. Serial No. 281,808.

usually in the past particular care has been taken to provide against the opportunity for the existence of air pockets in systems of this character. e

A further and highly important object of the invention is the provision of a brake control for mine hoists, that will attain these desirable results without increasing the complexity of the apparatus, without ncreasing materially its cost and without incorporating in it any sensitive or delicate part that may require frequent repair or replacement or otherwise affect the durable and efficient character of the apparatus.

Numerous other objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawin illustrating a preferred embodiment thereo On the drawing,

Figure 1 is a diagrammatic view of a brake control in which my present invention is embodied; and

Fig. 2 is an enlarged vertical section through the air cushion providing drum or dome.

For the purpose of illustrating my present invention, I have shown on the drawing .a sample layout of a brake control. Reference character 11 indicates a sump or drain reservoir from which the oil is delivered by pump 12 to an accumulator or pressure reservoir 13, through pipes 14 and 15. A. pipe connection through pipes 15, 16 and 17 valve 18, pipe 19, air drum 21, pipe 22, valve 23, pipes 24, 25 and. 26, connects the pressure reservoir or accumulator 13 with .a brake cylinder 27, adapted in any suitable or preferred manner to control the action of the brake, by lifting the brake weight 20. It will be understood of course that this weight is connected with the brake in the relieved or withdrawn, that is to say the brake-is normally set or applied, and the hoist can only be operated when the, comlnumcatlon through the pipe connection just mentioned is open and the pressure is felt in the cylinder in suflicient amount to counteract the positive brake applying means (not shown) with which brakes in mine hoists are usually provided. If, however, either valve 18 or valve 23-be closed the brake is applied as a result. Valve 18 is the valve under the control of the operator and the one utilized in the "normal operation of the hoist, and valve 23 is an emergency valve electrically or mechanically controlledto cut off communication through the pipe line under pre-determined conditions rendering it essential that the brake be applied and this Without any action by the operator. When either of the valves 23 and 18 is moved to interrupt the communication with the accumulator, it establishes communication with the reservoir 11 and the cylinder 27, the valves 18 and 23 being each three-way valves. The communication established by the valve 18 between the cylinder and the reservoir 11 is through pipes 28, 29 and 31 and that established by the valve 23 is through pipes 32, 29 and 31.

The air drum 21 shown in enlarged section, Fig. 2, provides merely a pocket in which a quantity of air may be contained, and is shaped to provide an enlarged upper chamber 33 and a restricted lower chamber 34.

, With this. lower chamber the-two "pipes 22 and 19, have free communications, their adjacent ends being'threaded into the wall of the .dome 21, leakage being prevented by stuffing boxes 35 or otherwise.

The air drum is preferably positioned between the two valves, although of course it might be otherwise located. It is not always, however, desirable to exert a softenmg or restraining nfluence upon the action of the hoist resulting from an application of the brake applied by action of the emerthat instant stopping is imperative.

gency valve 23, for conditions ma release of this pressure by a manipulation of its attendant advantages will be understood from the foregoing without further description, and it will be apparent that various changes may be made in the form, construction and arrangement-of. the parts of the brake control without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a brake control for mine hoists and the like, an incompressible fluid system including an accumulator, a thrust cylinder, a drain reservoir, and connections between the same including an air cushion and pipe and valve members, said air cushion and valve members being arranged in said connection to include the air cushioning means into direct communication with the thrust cylinder in releasing the brake and providing for its exclusion in applying the brake under certain emergency conditions.

2. A brake control for mine hoists and the like, comprising in combination an incompressible fluid system and a thrust cylinder, said system including an accumulator, and a drain reservoir, pipes connecting said accumulator with said thrust cylinder, a valve in said pipe connections, and cushioning means between said valve and said accumulator.

3. In a brake eontrol'for mine hoists and the like, the combination of a thrust cylinder for releasing the brake, means acting against pressure in said thrust cylinder for applying the brake, means for supplying oil under pressure to the thrust cylinder to release the brake and deliverable to said thrust cylinder in controlled amount and pressure to produce application of the brakes, and a cushion in said second mentioned means.

4. A brake control for mine hoists and the like, comprising in combination a brake cylinder, a means for supplying an incomressible liquid under premure to said cyliner, a manually .controlled valve in said means for controlling normal operation of the brake, and an emergency valve, and a cushion for influencing the action of the brake cylinder when the manually controlled valve is operated, said cushion being inactive when the emergency valve applies the brake.

5. A brake control for mine hoists and the like, comprising in combination a brake cylinder, a reservoir, a pipe connection between said reservoir and said brake c vlinder, two valves in the pipe connection from the reservoir to the cylinder, and an air drum or dome in said pipe connection and between said valves.

EZRA B. MEAD. 

